Three-Dimensional Stability of Two-Stage Slope in Inhomogeneous Soils

The three-dimensional (3D) stability calculations of soil slopes are often focused on homogeneous soils in the published literature. However, strength inhomogeneity is a common phenomenon in slope engineering. The purpose of this paper is to investigate the influence of strength inhomogeneity on the seismic and static 3D stability of a two-stage slope. The soil is inhomogeneous in the vertical direction only, and the slope is subjected to the horizontal earthquake force. Using a 3D failure mechanism, the internal energy is only dissipated along the sliding surface. The external rate of work is done by the soil weight and the earthquake force. Based on the upper bound theorem of limit analysis, the slope stability problem is formulated as a classical nonlinear programming problem. Coding the corresponding computer program, the stability factors of inhomogeneous soil slopes are obtained. When the inhomogeneous coefficient is zero, the present results are compared with those previously published solutions. Based on the comparisons, the approach of this paper is effective for estimating the 3D stability. A study is conducted to investigate the effects of the inhomogeneous coefficient on seismic and static stability factors of a two-stage slope.